Snap switch actuator

ABSTRACT

A method and apparatus for actuating a contact carrying snapover center spring member in an electrical switching device is disclosed. The spring member includes a stressed contact carrying arm which assumes either of two oppositely directed, bowed rest positions and at least one stressing arm crimped to be shorter than the contact carrying arm. The spring member is mounted in cantilever fashion with the contact positioned for cooperative interaction with a fixed contact. The actuator includes camming means acting in the plane of the spring against an area near the free end of the contact carrying arm of the spring to force it from one bowed rest position to its opposite bowed position.

United States Patent [191 Bunnell et al.

SNAP SWITCH ACTUATOR Inventors: Edward Dennman Bunnell, Palm Harbor; Stuart L. Parsons, Belleair-Beach, both of Fla.

Assignee: AMP Incorporated, Harrisburg, Pa. Filed: May 25, 1973 Appl. No.: 364,156

US. Cl. 200/67 DA Int..Cl. H0lh 13/36 Field of Search 200/67 D, 67 DA, 67 DB,

200/168 E, 67 R; 70/100 P References Cited UNITED STATES PATENTS Burch 200/67 DA Aug. 6, 19.74

3,550,055 12/1970 Grover 200/67 DA Primary Examiner-David Smith, Jr.

[5 7] ABSTRACT A method and apparatus for actuating a contact carrying snap-over center spring member in an electrical switching device is disclosed. The spring member includes a stressed contact carrying arm which assumes either of two oppositely directed, bowed rest positions and at least one stressing arm c'rimped to be shorter than the contact carrying arm. The spring member is mounted in cantilever fashion with the contact positioned for cooperative interaction with a fixed contact. The actuator includes camming means acting in the plane of the spring against an area near the free end of the contact carrying arm of the spring to force it from one bowed rest position to its opposite bowed position.

11 Claims, 13 Drawing Figures PAIENIEM 6574 SHEEI 1 [1F 4 PATENTEB AUG 5 '9 sum 3 or 4 1 SNAP SWITCH ACTUATOR BACKGROUND OF THE INVENTION 1. The Field of the Invention The present invention relates to switch actuating means and in particular to actuating means lying in the plane of a snap-over center spring and acting to move the spring from one rest position to another.

The Prior Art Switches employing snap-over center contact carrying springs have been known for a long time, for example, see US. Pat. No. 3,389,902 which teaches making snap-over center springs. In these switches, a contact carrying snap-over center spring element is formed by at least two substantially parallel arms which are connected at both ends. One arm is crimped to be foreshortened causing the other arm to be always under compression and assume a bowed rest position directed to either side of the crimped arm. A contact is fixed on the bowed arm and makes and breaks with a stationary contact in an associated housing. This type of switch is commonly actuated by means acting transversely of the spring to deflect one end thereof until the bowed arm is forced to snap-over center to the other rest position. Many of these switches are, however, only in the second position while the actuating button is depressed.

Examples of switches employing snap-over center spring contact members may be found in US. Pat. Nos. 1,668,974; 2,340,615; 2,363,280; 2,518,255; 2,6l6,996; 2,700,079; 2,734,958; 2,773,955; 3,120,590; and 3,550,055; A modified type of spring which acts in a similar fashion is shown in US. Pat. Nos. 1,960,020 and 2,840,656.

SUMMARY OF THE INVENTION The invention may be incorporated in several different switch embodiments and includes'a snap-over center contact spring having at least two substantially parallel arm portions extending from a base portion and joined at the opposite end by an end portion. One of the arms has at least one contact fixed thereon. The other of the arms are crimped to be shorter in length than the contact bearing arm which becomes bowed. The base of the contact spring is fixed with the arms extending therefrom in cantilevered fashion with the contact lying opposite a stationary contact in an associated housing. Actuating means, including wedging means, are mounted to act in the plane of the spring against the bowed arm to force it from one to the other rest position. The end of the spring is allowed a restricted amount of lateral movement so that it will be repositioned with respect to the actuating means each time the spring goes from one rest position to the other.-

It is therefore an object of the present invention to teach a new means and method for actuating snap-over center spring means whereby such contact carrying springs may be used in many types of switches including both push pull switches and line switches.

It is also an object of the present invention to construct a snap-over center switch which will utilize fully both rest positions of the over centered spring and yet be actuated by a single actuator moving along a rectilinear path lying in the plane of the spring.

It is a further object of the present invention to construct a switch using a snap-over center contact carrying spring which may be used as a line switch and actuated by a wedge member moving transversely in the plane of the spring.

It is yet a further object of the present invention to construct a switch using a snap-over center contact carrying spring which may be used as a push pull switch actuated by a blade moving reciprocally in the plane of the spring to engage the bowed arm of the spring.

It is still another object of the present invention to produce a snap-over center spring switch which is reliable in operation and which can be readily and economically produced.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an exploded perspective view of a first embodiment of a snap-over center line switch incorporating the actuating means of the present invention;

FIG. 2 is a vertical longitudinal section through the switch of FIG. 1;

FIG. 3 is a top plan view of the switch of FIG. 1 with the top removed and the contacts in a closed position;

FIG. 4 is a top plan view similar to FIG. 3 showing the position of the parts with the actuating lever depressed;

FIG. 5 is a top plan view similar to FIG. 3 showing the contacts in an open position;

FIG. 6 is a transverse vertical section through the subject switch taken along line 6--6 of FIG. 3;

FIG. 7 is a transverse vertical section through the subject switch taken along line 7'-7 of FIG. 3;

FIG. '8 is a transverse vertical section through the subject switch taken along line 88 of FIG. 4; j 7

FIG. 9 is a transverse vertical section through the subject switch taken along line 99 of FIG. 5;

FIG. 10 is an exploded perspective view of a snapover center switch incorporating the subject actuation means in a push pull embodiment;

FIG. 11 is a top plan view, partially in section, showing the switch of FIG. 10 with one set of contacts closed;

FIG. 12 is a top plan view, similar to FIG. 11, showing an intermediate step in changeover of the contacts; and

FIG. 13 is a top plan view, similar to FIG. 1 1, showing the second set of contacts closed.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The principles of the subject actuating means for a snap-over center line switch are illustrated in a first embodiment in FIGS. 1 to 9. The line switch includes a housing base 10 and mating housing cover 12. The base 10 is formed with a central recess 14 located between two spaced line channels 16, 18. A spring groove 20 is formed in one end wall of the recess and a terminal groove 22 in the other end of the recess. A contact groove 24 is formed in one side wall of the recess and communicates with channel 18. v

A terminal contact 26 is fixed in groove 24 with a stationary contact 28 extending into recess 14.

A snap-over center spring member 30 is mounted cantilever fashion from terminal 32 which is fixed in groove 22. The spring member 30 includes a base portion 34, a pair of spaced arm portions 36, 38 extending from the base portion, and an end portion 40 connecting the ends of the arms remote from the base. A movable contact 42 is fixedly mounted on upper arm 36 while the lower arm 38 is foreshortened-by crimp 44. The crimp causes arm 36 to always be under compression and assume one of two rest positions, namely, bowed to either side of arm 38.

The cover housing 12 has a central aperature 46 through'which the actuating lever 48 extends. The I lever has a pair of transversely extending first pin members 50 which are received in recesses 52 in the cover and serve as pivots for the lever as it is rotated. A pair of transversely extending second pins 54 are spaced forwardly on the lever from the first pins and engage in recesses 56 in the cover to limit the upward or clockwise travel of lever 48. Leaf spring 58 is received in groove 60 in the end of the lever and serves to bias the lever in the clockwise direction. A blade 62 depends from the free end of the lever 48 and has a wedge shape formed by a pair of tapered, rearwardly converging surfaces 64, 66, as best seen in FIGS. 7 to 9. It should be here noted that the bottom edge 68 of the blade lies closely adjacent the upper edge of the spring member, as seen in FIG. 2.

A twin lead line cord 70 is positioned in the housing with continuous lead 72 lying in channel 16 and discontinuous lead 74 lying in channel 18. One free end of lead 74 is fixed to terminal 26 by any conventional means, such as crimping, while the other free end is similarly fixed to terminal 32.

The operation of this embodiment of the actuator will be explained with reference to FIGS. 3 to and 7 to 9. The switch is shown in FIGS. 3 and 7 with the contacts 28, 42 closed. The contacts are opened by depressing lever 48 against the biasing force of spring 58 to bring the lower edge 68 of blade 62 into engagement with the upper arm 36 of spring member 30. This arm is under compression, due to the crimp 44, and normally will assume either of the two over center rest positions, as shown in FIGS. 3 and 5. The compression will never allow the spring to lie in a centered rest position. The edge 68 of the wedge, and the inclined wedge surface 66 in this instance, engage the tensioned and bowed upper arm 36 of the spring member 36 and force it from the over-centered rest condition of FIGS.- 3 and 7 toward the opposite over-centered rest position of FIGS. 5 and 9, as shown in FIGS. 4 and 8. Upon release of pressure against the lever 48, the spring 58 will cause a return upward movement of the lever 48 which will be halted when pins 54 engage in recesses 56. When the bottom edge 68 of blade 62 clears spring member 30, the compression forces in the spring will cause movement of the free end 40 of the spring from one side of groove 20 to the other, as can best be seen by comparing FIGS. 7 and 9. This movement will reposition the spring member 30 to lie on the opposite side of the wedge shaped blade 62 from that shown in FIG. 3. Without this movement of the free end of the spring member to reposition it with respect to the actuating lever, the switch would not be able to operate.

The second embodiment of the subject actuator is shown in FIGS. to 13 in a push pull type of switch. This switch includes a housing 76 having a base portion 78 with a block like actuator support 80 on one end and a terminal support 82 on the other end. An axial bore 84 extends partially through the actuator support and is in communication with a profiled slot 86. A cylindrical sleeve 88 is positioned in bore 84 with axial slot 90 aligned with profiled slot 86. Elongated slots 92,

94 are formed in a side wall of the actuator support and sleeve 88, respectively, and are aligned with each other. An actuator button means 96 is reciprocally mounted within sleeve 88 and includes shaft 98 having button 100 mounted on the end extending from the housing and actuator blade 102 fixed to the other end and directed toward slot 90. Helical compression spring 104 is mounted around shaft 98 between sleeve 88 and button 100. Pin 106 is fixed in shaft 98 to extend through elongated slots 92, 94 and serves both to keep the actuator button means 96 in proper orientation as well as to limit its reciprocal travel.

A first terminal 108 is mounted on one side of the housing and includes a resilient cantilevered arm 110 carrying contact 1 12 on its free end and a lead connecting bracket 114. Both the bracket and arm are secured to the housing by screw 116. A second similar terminal 118 is mounted on the opposite side of the housing and includes arm 120, contact 122, lead connecting bracket 124 and mounting screw 126. The terminals are positioned so that contacts 112 and 122 are in opposing spaced relationship.

A third terminal 128 is mounted on terminal support 82 and includes a lead connecting bracket 130 and snap-over center contact spring 132. Both the bracket 130 and spring 132 are secured to the support 82 by screw 134. The contact spring 132 is a modified version of the spring described above relative to the first embodiment. This spring has a base portion 136 with arms 138, 140, and 142 extending in parallel spaced relation therefrom and joined at their opposite ends by end portion 144. Arm has contacts 146 and 148 fixed thereon and arms 138 and 142 have crimps 150 and 152, respectively, formed therein to foreshorten these arms thereby placing arm 140 under constant compression. Cam portions 154 and 156 are formed on opposite sides of arm 140 adjacent the end 144.

The operation of this switch embodiment is somewhat similar to the first switch embodiment. This embodiment also depends on the fact that the outer arms of the spring contact member are foreshortened by the crimps so that the middle arm will never rest in a centered position but will always lie in either of two rest positions, as shown in FIGS. 11 and 13.

Referring to FIG. 11, contacts 112 and 146 are shown closed. When the push button 100 is depressed, moved to the left as shown in FIGS. 11 to 13, the actuator blade 102 will be brought into engagement with cam wedge 156 forcing the contact spring member 132 to move from the first rest position shown, with contacts 112 and 146 engaged, to a second rest position, with contacts 122 and 148 engaged. When the push button 100 is released, spring 104 drives it to the right, as shown in FIGS. 11 to 13, until blade 102 clears the end of the contact spring 132. When the blade is clear of the spring, the spring moves further towards its second rest position with the end 144 moving from one side of the slot 86 to the other side. Thus the spring will be positioned so that the blade on its next inward movement will contact wedge portion 154.

It should be noted that since contacts 112 and 122 are mounted on the ends of resilient arms 1 10 and 120, respectively, they will be biased toward engagement with their respective contacts 146 and 148 on the spring member. The resiliency of the arms will assure a firm engagement of the closed contacts.

It is within the scope of the present invention to replace the blade 102 and cam portions 154 and 156 with a single wedge shaped cam member, not shown, fixed on the end of shaft 98. This cam member would act in the same manner as cam 62 of the first embodiment to actuate the spring 104. The spring 104 can also be replaced by a spring similar to spring 30 of the first embodiment.

It will be appreciated that the aforementioned and other desirable objects have been achieved by the two described embodiments; however, it should be emphasized that the particular embodiments of the invention which have been illustrated and described herein are intended as merely illustrative and not as restrictive of the scope of the invention since other changes and modifications may be forseen without departing from the spirit or essential characteristics of the invention.

What is claimed is:

l. A switch comprising:

a spring blade having at least two spaced arms connected at both ends, one of said arms having a contact near the middle thereof and the other of said arms being crimped to keep said one arm constantly under compression and in a bowed condition directed to either side of the other of said arms;

housing means including means to mount said spring blade by one end in a cantilevered fashion and means to restrict movement of the free end of said spring blade;

at least one fixed contact means mounted in said housing to be selectively engaged by the contact on said spring blade; and

actuating means acting against said bowed arm adjacent the free end thereof and substantially in the plane of said spring blade whereby said spring blade is moved between bowed positions with said contacts engaged and disengaged and the free end of said spring blade is repositioned with respect to said actuating means.

2. A switch according to claim 1 wherein said actuating means comprises:

lever means one end of which is pivotally mounted in said housing means; and

blade means depending from the free end of said lever means and disposed to engage said spring blade transversely to the longitudinal axis of said blade, whereby said spring blade is caused to snapover to its other bowed condition.

3. A switch according to claim 2 wherein said blade means has a wedge shaped configuration.

4. A switch according to claim 2 wherein said blade means has a wedge shaped profile defined by two inclined surfaces tapering rearwardly towards the pivoted end of the lever means.

5. A switch according to claim 2 further comprising spring means biasing said lever means to hold said blade means out of engagement with said spring blade.

6. A switch according to claim 5 wherein said spring means is a leaf spring acting on the pivoted end of said lever means.

7. A switch according to claim 1 wherein said actuating means comprises:

push button means mounted in said housing means for reciprocal movement parallel to the longitudinal axis of said spring blade;

said push button means including blade means adapted to engage said spring blade.

8. A switch according to claim 7 wherein said blade means is rectilinear; and

cam surfaces are formed on each side of said one arm of said spring blade, whereby said blade means selectively engaging said cam surfaces causes snapover movement of said spring blade to its other bowed condition.

9. A switch according to claim 7 wherein said blade means is wedge shaped.

10. A switch according to claim 7 further comprising spring means biasing said push button to hold said blade means out of contact with said spring blade.

11. A switch according to claim 1 further comprising two stationary contacts mounted in said housing means in opposing spaced relationship on opposite sides of said spring blade;

first and second terminal means each connected to one of said stationary contacts; and

third terminal means connected to said one end of said spring blade, whereby actuation of said spring blade causes selective connection of said third terminal means with said first and second terminal means. 

1. A switch comprising: a spring blade having at least two spaced arms connected at both ends, one of said arms having a contact near the middle thereof and the other of said arms being crimped to keep said one arm constantly under compression and in a bowed condition directed to either side of the other of said arms; housing means including means to mount said spring blade by one end in a cantilevered fashion and means to restrict movement of the free end of said spring blade; at least one fixed contact means mounted in said housing to be selectively engaged by the contact on said spring blade; and actuating means acting against said bowed arm adjacent the free end thereof and substantially in the plane of said spring blade whereby said spring blade is moved between bowed positions with said contacts engaged and disengaged and the free end of said spring blade is repositioned with respect to said actuating means.
 2. A switch according to claim 1 wherein said actuating means comprises: lever means one end of which is pivotally mounted in said housing means; and blade means depending from the free end of said lever means and disposed to engage said spring blade transversely to the longitudinal axis of said blade, whereby said spring blade is caused to snap-over to its other bowed condition.
 3. A switch according to claim 2 wherein said blade means has a wedge shaped configuration.
 4. A switch according to claim 2 wherein said blade means has a wedge shaped profile defined by two inclined surfaces tapering rearwardly towards the pivoted end of the lever means.
 5. A switch according to claim 2 further comprising spring means biasing said lever means to hold said blade means out of engagement with said spring blade.
 6. A switch according to claim 5 wherein said spring means is a leaf spring acting on the pivoted end of said lever means.
 7. A switch according to claim 1 wherein said actuating means comprises: push button means mounted in said housing means for reciprocal movement parallel to the longitudinal axis of said spring blade; said push button means including blade means adapted to engage said spring blade.
 8. A switch according to claim 7 wherein said blade means is rectilinear; and cam surfaces are formed on each side of said one arm of said spring blade, whereby said blade means selectively engaging said cam surfaces causes snap-over movement of said spring blade to its other bowed condition.
 9. A switch according to claim 7 wherein said blade means is wedge shaped.
 10. A switch according to claim 7 further comprising spring means biasing said push button to hold said blade means out of contact with said spring blade.
 11. A switch according to claim 1 further comprising two stationary contacts mounted in said housing means in opposing spaced relationship on opposite sides of said spring blade; first and second terminal means each connected to one of said stationary contacts; and third terminal means connected to said one end of said spring blade, whereby actuation of said spring blade causes selective connection of said third terminal means with said first and second terminal means. 